Continuous filament glass strands may be produced by flowing a multiplicity of molten streams from a feeder containing a supply or body of molten glass and then applying a pulling force to the individual streams sufficient to attenuate the streams into continuous filaments, which are combined subsequently into a strand. A winder packages the strand on a collector such as a tube. The collector acts as the attenuating means through high speed rotation provided by the winder. When the required amount of strand winds into a package on the collector, the winder discontinues the rotation of the collector, which gives rise to an interruption in the attenuation of the glass filaments long enough to permit an operator to interchange an empty tube collector for the pull tube.
An interruption is detrimental to the process of forming continuous filament glass. The proper thermal conditioning of the molten glass for particular filament size and the like require strict adherence for uniformity of product; such conditioning tends to change during periods of interruption. Furthermore, if the filament attenuation is intermittent, the process must be started anew after each change of the collector. Such requires that an operator consume much time getting all the hundreds or even several thousands of streams of molten glass flowing properly from their feeder source by pulling the filaments over size applicators, gathering shoes and perhaps even strand splitters to ready the process to attenuate the streams into the filaments.
Thermal conditioning of the molten streams and the difficulty of properly flowing and attenuating all of the molten streams of glass into filaments arising from interruptions also pertains to the start-up of a cold feeder prior to collecting the first wound package after commencing operations.
Because the practice of having operators draw the filaments from the streams by hand at start-up and between packages was not satisfactory, there arose the practice of employing "secondary" means for advancing a strand such as cooperating rolls where one or both of the rolls are driven. Such a "secondary" means for advancing strand is shown and described in U.S. Pat. No. 3,539,317. During times of interruption the "secondary" means advance the strand to subsequently keep thermal continuity, etc.
"Secondary" means such as the cooperating rolls that have parallel teeth on the peripheral surfaces shown in U.S. Pat. No. 3,539,317 have been used in the industry for some time. With such prior art advancing means the strand must be securely placed between the rolls before the strand will be advanced by the rolls; that is, if a strand is laid at the end of the rolls it would not be advanced unless and until an operator positioned the strand between the rolls. When starting up or feeding these prior art rolls by dropping strand from above, it is necessary to have an operator take the strand dropped from above and place it between the rolls before the strand is advanced by the rolls. Thus, an operator who pushes or positions the strand between the rolls is necessary and critical to begin the advancement of the strand by the rolls. It would be desirable to have a method and apparatus for advancing strand wherein the placement of the strand between a set of pulling rolls is less dependent upon an operator.
Thus, it can be seen that improvement method and apparatus are needed.